Braking device for vehicle

ABSTRACT

A braking device for vehicle comprises a splash guard including a plate-like member arranged facing to a friction portion of a circular disk-shaped rotor with a wheel axis as a rotation center, arranged close to a knuckle W1 and mounted on the knuckle, wherein the splash guard includes a fixing plate fixed to the knuckle, a wall with holes standing up from the fixing plate towards the rotor, and a plurality of cooling holes configured with through-holes passing through the wall with holes, wherein the plurality of cooling holes include openings arranged along the wall with holes, and the opening areas of cooling holes arranged upper side of the wheel axis are set to be smaller than the opening area of a cooling hole arranged lower side of the wheel axis.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2018-184910 filed on Sep. 28, 2018; the entire contents of which are incorporated herein by reference.

TECHNICAL FIELD

The present invention relates to a braking device for vehicle which performs breaking of a vehicle.

BACKGROUND ART

As a braking device for a vehicle, a disk brake is widely employed, which performs breaking by sandwiching a rotor of a circular disk-shaped plate with pads (friction materials) on both plate surfaces of the rotor, which rotor rotates together with a wheel. However, in such a disk brake, when a dust, a gravel, or a muddy water and the like is caught between the rotor and the pads, and when breaking is carried out in that state, there may be a risk that a sufficient breaking force may not be obtained.

Thus, in order to prevent any foreign matter from entering into between the rotor and the pads, the rotor is conventionally covered with a splash guard.

For example, in a braking device for a vehicle, as disclosed in Japanese open-laid patent application no. 2002-276698, a splash guard including holes for fixation and holes for feeding through the cables etc. is disclosed.

Further, in a braking device for a vehicle, as disclosed in Japanese open-laid utility patent application no. S62-204044, a splash guard provided with embossing for reinforcement is disclosed.

SUMMARY OF INVENTION Technical Problem

When the rotor is constructed to be covered with a splash guard, there is a risk of insufficient cooling due to heat build-up produced during braking.

Therefore, conventionally, cooling holes are provided to the splash guard. However, by providing the cooling holes, there arises a new problem that the foreign matters entered through the cooling holes into between the splash guard and the rotor may hardly be eliminated.

The present invention is created considering the above problem and aims at providing a braking device for a vehicle, including a splash guard which, along with exerting a sufficient cooling performance, allows suppression of foreign matters entering into between the splash guard and the rotor.

Solution to Problem

In order to solve the above problem, a braking device according to the present invention includes a splash guard including a plate-like member arranged facing to a friction portion of a circular disk-shaped rotor with a wheel axis as a rotation center, arranged close to a knuckle and mounted on the knuckle, wherein the splash guard includes a fixing plate fixed to the knuckle, a wall with holes standing up from the fixing plate towards the rotor, and a plurality of cooling holes configured with through-holes passing through the wall with holes, wherein the plurality of cooling holes include openings arranged along the wall with holes, and the opening areas of cooling holes arranged upper side of the wheel axis are set to be smaller than the opening area of a cooling hole arranged lower side of the wheel axis.

Advantageous Effect of the Invention

According to the present invention, a braking device including a splash guard, which enables suppressing of foreign matters entering into between the splash guard and the rotor, can be provided.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 shows a front view of a braking device according to an embodiment of the present invention, in which a splash guard is assembled to a knuckle.

FIG. 2 is an enlarged view, seen from the direction A in FIG. 1.

FIG. 3 is an enlarged view, seen from the direction B in FIG. 1.

FIG. 4 is an enlarged view of the portion C of FIG. 1.

FIG. 5 is an enlarged view, seen from the direction D in FIG. 1.

FIG. 6 is an enlarged view of the portion E of FIG. 1.

FIG. 7 is an enlarged view, seen from the direction F in FIG. 1.

DESCRIPTION OF EMBODIMENTS

An embodiment according to the present invention will be described in detail referring to the figures. It should be noted that, in the following explanation, a same reference number is given to a same element, and accordingly repeating explanations are omitted.

A disk brake BR (a braking device for a vehicle) according to the present embodiment is configured for braking a front wheel (not shown in the figure) which is a steering wheel, and is installed on a knuckle (of a vehicle body).

Further, the disk brake BR according to the present embodiment includes a rotor B1, a caliper B2 and, in addition, a splash guard 10.

In the disk brake BR, the caliper B2 is activated by a driver's braking operation. Then, as the caliper B2 is activated, the braking pads (not shown in the figure) arranged opposing to each other within the caliper B2 are pressed onto the rotor B1 which rotates together with the wheel, by which braking is carried out.

With the disk brake BR configured as above, while the vehicle is travelling, foreign matters such as dust, gravel, and muddy water, etc. are whirled up around the wheel.

Therefore, the foreign matters, which have been whirled up, occasionally may be attached to the rotor B1, or may enter into a gap between the rotor B1 and the braking pads.

Further, if braking is carried out in a state that a foreign matter is sandwiched between the rotor B1 and the braking pads, there is a risk that a desired braking force may not be obtained, and, in addition, there is a risk that the rotor B1 and the braking pads may be damaged.

Further, when a hub bearing (not shown in the figure) is splashed with muddy water, due to various particles contained in the muddy water, there is a risk that wearing of the hub bearing may be enhanced.

Therefore, in the disk brake BR (a brake device for a vehicle) according to the present embodiment, a splash guard 10 is provided to suppress the foreign particles to enter into the gap between the rotor B1 and the braking pads. Next, configurations of respective parts of the disk brake BR will be explained (refer to FIG. 1).

The rotor B1 (refer to FIGS. 2, 3) is pivotably supported via a hub bearing, by which the rotor can freely rotates together with the front wheel (vehicle wheel) against the knuckle (vehicle body). Further, the rotor B1 has a general circular disk-shape centered around the wheel axis CW of the front wheel (vehicle wheel) and is arranged facing parallel to the rotational plane of the front wheel (vehicle wheel).

The rotor B1 includes a rotor supporting portion and a friction portion B1 b.

The rotor supporting portion constitutes a center portion of the general circular disk-shaped rotor B1.

The friction portion B1 b has an annular shape and constitutes an outer portion of the general circular disk-shaped rotor B1.

In other words, in the radially outer side of the rotor supporting portion, the friction portion B1 b and the rotor supporting portion are integrally formed sharing a center.

The caliper B2 is mounted in a portion of the knuckle which faces the rear edge of the rotor B1 (refer to FIG. 1).

Further, the caliper B2 has a general U-shape, wherein the friction portion B1 b is accepted inside of the U-shape in its recessed portion and is mounted on the knuckle to sandwich the friction portion B1 b.

Namely, the caliper B2 is arranged to stride over the friction portion in the direction of plate thickness.

Further, the braking pads are arranged inside of the caliper B2, allowing the pads to move onto the friction portion B1 b.

Thus, by a braking operation of the driver, the braking pads are pressed against the friction surface B1 c of the friction portion B1 b, through which a friction force is generated between the braking pads and the friction portion B1 b when the braking pads are pressed against the friction surface B1 c and the friction force works as the braking force.

The splash guard 10 is arranged between the rotor B1 and the knuckle and is fixed to the knuckle , covering the rotor B1 starting from inner side in the vehicle body width direction.

Further, the splash guard 10 includes a guard main body 11, a fixing portion 12, a cutout portion 13, a wall with holes 14, cooling holes 30, an offset wall 15, and an offset portion 20.

The guard main body 11 defines the outline of the splash guard 10 and is configured with a member of a circular disk-shape which follows the outline of the rotor B1.

The fixing portions 12 are configured to fix the splash guard 10 to the knuckle and are arranged as a general circular shape at three positions of a fixing plate 12 a which faces to the rotor supporting portion of the rotor B1.

In the fixing portion 12, a through hole passing through the fixing plate 12 a is provided. The splash guard 10 is fixed to the knuckle by screwing a screw, which passes through the fixing portion 12, into a female screw formed on the knuckle.

It should be noted that, regarding the mean for fixing the fixing portion 12 to the knuckle, any mean can be appropriately employed, if the mean does not hinder the rotation of the rotor B1 and wheel and if the mean does not hinder the movement of the caliper B2.

Further, a space is formed between the fixing plate 12 a and the rotor B1, which space is called as a fixed space B3 (refer to FIG. 1). In addition, the fixed space B3 functions as an elimination route 50 for eliminating the foreign matters to outside. It should be noted that the fixed space B3 is communicated with the cutout portion 13.

The cutout portion 13 is a cutout formed in a portion of the guard main body 11 which faces to the caliper B2 when the splash guard 10 is assembled to the knuckle. Further, the cutout portion 13 is cut out following the outline of the caliper B2 (refer to FIG. 1).

In addition, the splash guard 10, receiving the caliper B2 in the cutout portion 13, is arranged close to and opposing to the friction surface B1 c of the friction portion B1 b to be overlapped therewith.

Further, a region, which is formed by the cutout portion 13, the outer circumferential surface of the caliper B2, and the friction surface B1 c of the rotor B1 function as an elimination route 50 (a second elimination route 51).

The wall with holes 14 is curved like an arc along the circumferential edge of the fixing plate 12 a and stands up from the fixing plate 12 a towards the rotor B1.

Further, the wall with holes 14 connects the fixing plate 12 a and the guard main body 11.

In addition, the wall with holes 14 discontinues at lower side of the wheel axis CW.

Next, it will be explained about cooling holes 30 (refer to FIG. 1).

The cooling holes 30 are configured with five through-holes which pass through the wall with holes 14, wherein all cooling holes are arranged in the front side relative to the wheel axis CW.

Further, all cooling holes 30 are opened to the radial direction and are communicated with the fixed space B3.

In addition, the cooling holes 30 includes upper cooling holes 31 and a lower cooling hole 32.

The upper cooling holes 31 are configured with four cooling holes, which are arranged upper side relative to the wheel axis CW. Further, the upper cooling holes 31 are arranged so that each opening area of the cooling holes is smaller than the lower cooling hole 32.

The lower cooling hole 32 is configured with one remaining cooling hole 30, which is arranged lower side relative to the wheel axis CW.

The offset wall 15 is curved like an arc and stands up from the guard main body 11 so that the offset wall 15 is arranged opposing to the cooling holes and is arranged radially outer side relative to the wheel axis CW as a center axis.

Further, the offset wall 15 connects the guard main body 11 and the offset portion 20.

Further, the offset wall 15 discontinues at a portion which overlaps in radial direction with a portion of the wall with holes 14 where the wall with holes 14 discontinues at lower side of the wheel axis CW. In addition, the portion of the offset wall 15, where the offset wall 15 discontinues at lower side of the wheel axis CW, and the portion of the wall with holes 14, where the wall with holes 14 discontinues, are connected together.

Next, it will be explained about the offset portion 20 (refer to FIG. 1).

The offset portion 20 is a portion which is offset in the direction along which the spacing between the splash guard 10 and the friction surface B1 c of the rotor B1 becomes larger (refer to FIG. 1).

Further, the offset portion 20 is configured with a recessed portion having a general trapezoidal cross section which is narrowed as the distance between the plate surface 11 a of the guard main body 11 and the friction portion B1 b becomes larger (refer to FIGS. 2-7).

Further, the offset portion 20 includes an upper offset portion 21 and a lower offset portion 22 (refer to FIGS. 1, 2).

The upper offset portion 21 is formed on the guard main body 11 at a peripheral portion positioned front side relative to the wheel axis CW and upper side relative to the wheel axis CW.

It should be noted that the upper offset portion 21 works as the elimination route 50 (first elimination route 52), through which the foreign particles entered into between the splash guard 10 and the rotor B1 are eliminated (refer to FIG. 1).

The lower offset portion 22 is formed on the guard main body 11 at front side relative to the wheel axis CW and at a lower peripheral portion relative to the wheel axis CW.

It should be noted that the lower offset portion 22 (the radially outside of the offset wall) is communicated with the cutout portion 13.

Further, the lower offset portion 22 works as the elimination route 50 (third elimination route 53), through which the foreign particles entered into between the splash guard 10 and the rotor B1 are eliminated (refer to FIG. 1).

Next, it will be explained about the function of the splash guard 10 (refer to FIG. 1).

When a foreign matter strikes on the wall with holes 14 in such a way that the foreign matter falls down from upper side or is splatted from the ground and so on, the foreign matter is repelled to front side directly.

When a foreign matter enters into the upper offset portion 21 in such a way that the foreign matter falls down from upper side or is splatted from front side and so on, the foreign matter will be eliminated through the first elimination route 52 towards the front side.

When a foreign matter strikes on the caliper B2 in such a way that the foreign matter falls down from upper side or is splatted from the ground and so on, the foreign matter will be eliminated through the second elimination route 51 towards rear side of the caliper B2.

Thus, there are two routes for eliminating the foreign matter, when the foreign matter passes through the upper cooling holes 31 and enters into the fixed space B3 in such a way that the foreign matter falls down from upper side or is splatted from front side and so on.

In the first route, the foreign matter which passed through the upper cooling holes 31 is eliminated through the fixed space B3 and the second eliminating route towards rear side of the caliper B2.

In the second route, the foreign matter which passed through the upper cooling holes 31 is eliminated through the fixed space B3 and the lower offset portion 22 downwards to outside.

When the foreign matter enters into the lower offset portion 22 in such a way that the foreign matter is splatted from the ground and so on, the foreign matter is repelled from the offset wall 15 and is eliminated downwards.

When the foreign matter passed through the lower cooling hole 32 and enters into the fixed space B3 in such a way that the foreign matter is splatted from the ground and so on, the foreign matter is eliminated from the fixed space B3 through the lower offset portion 22 downwards to outside.

Next, it will be explained about the effect of the disk brake (a braking device for a vehicle) according to the present embodiment.

In the present embodiment, since the upper cooling holes 31 are arranged at higher positions than the lower cooling hole relative to the ground, the opening area of an upper cooling hole is set to be smaller than the opening area of the lower cooling hole. Further, the upper cooling hole includes a plurality of holes.

This is because the foreign matter splatted from the ground flies higher when the particle size is smaller and flies lower when the particle size is larger, and therefore the opening area is set according to a particle size of a splatted foreign matter.

With this configuration, along with exerting a sufficient cooling performance, it is possible to suppress the entrance of the foreign particles.

In the present embodiment, the offset wall 15 is arranged to stand up opposing to the cooling holes (upper cooling holes 31, lower cooling hole 32).

With this configuration, since the foreign matters going to the cooling holes 30 are blocked by the offset wall 15, it is possible to further suppress the foreign particles entering through the cooling holes 30.

In the present embodiment, the offset portion 20 (upper offset portion 21, lower offset portion 22) is provided at radially outside of the offset wall 15 which opposes to the cooling holes 30 (upper cooling holes 31, lower cooling hole 32). Further, the offset portion 20 constitutes the eliminating route 50 (first eliminating route 52, third eliminating route 53).

With the configuration described above, the foreign matter going to the cooling holes 30 are blocked by the offset wall 15 and are eliminated from the offset portion 20 to outside.

As a result, it is possible to further suppress the entrance of the foreign matters.

In the present embodiment, the wall with holes 14 discontinues at lower side of the wheel axis CW. Due to this configuration, the fixed space B3 (the radially inside of the offset wall) and the lower offset portion 22 (the radially outside of the offset wall) are communicating.

As a result, the foreign matters which entered through the cooling holes 30 can be quickly eliminated to outside.

In the present embodiment, the region, which is formed by the cutout portion 13, the outer circumferential surface of the caliper B2 and the friction surface B1 c of the rotor B1, configures the elimination route 50 (the second elimination route 51) for eliminating the foreign matters.

As a result, the foreign matters which entered into between the cutout portion 13 and the caliper B2 can be quickly eliminated to outside.

Although the invention has been described above by reference to certain embodiments of the invention, the invention is not limited to the embodiments described above. Modifications and variations of the embodiments described above will occur to those skilled in the art, in light of the above teachings. The scope of the invention defined with reference to the following claims. 

1. A braking device for vehicle comprising: a splash guard comprising a plate-like member arranged facing to a friction portion of a circular disk-shaped rotor with a wheel axis as a rotation center, arranged close to a knuckle and mounted on the knuckle, wherein the splash guard comprises a fixing plate fixed to the knuckle, a wall with holes standing up from the fixing plate towards the rotor, and a plurality of cooling holes configured with through-holes passing through the wall with holes, wherein the plurality of cooling holes comprise openings arranged along the wall with holes, and the opening areas of cooling holes arranged upper side of the wheel axis are set to be smaller than the opening area of a cooling hole arranged lower side of the wheel axis.
 2. The braking device for vehicle according to claim 1, wherein the splash guard comprises an offset wall being arranged radially outside of the cooling hole centered around the wheel axis and standing up opposing to the cooling hole.
 3. The braking device for vehicle according to claim 2, wherein the splash guard comprises an offset portion being arranged at peripheral portion positioned radially outside of the cooling hole and being offset by the offset wall in a direction along which a spacing between the splash guard and the friction portion becomes larger.
 4. The braking device for vehicle according to claim 2, wherein the wall with holes discontinues at lower side of the wheel axis CW, and a portion of the offset wall 15, where the offset wall 15 discontinues at lower side of the wheel axis CW, and a portion of the wall with holes 14, where the wall with holes 14 discontinues, are connected together.
 5. A braking device for vehicle comprising: a splash guard comprising a plate-like member arranged facing to a friction portion of a circular disk-shaped rotor with a wheel axis as a rotation center, arranged close to a knuckle and mounted on the knuckle, wherein the splash guard comprises an offset wall arranged at a peripheral portion positioned at front side relative to the wheel axis and arranged to stand up in a direction along which a distance to the friction portion enlarges, an offset portion of which plate surface is offset by the offset wall in a direction along which a spacing between the splash guard and the friction portion becomes larger, wherein the offset portion constitutes a first elimination route.
 6. The braking device for vehicle according to claim 5, wherein the splash guard comprises a second elimination route which is formed with a friction surface of the rotor, a circumferential surface of a caliper arranged to stride over the friction portion of the rotor in a direction of plate thickness, and a cutout portion cut out following an outline of the caliper.
 7. The braking device for vehicle according to claim 6, wherein the offset wall stands up being curved like an arc centered around the wheel axis and being discontinued at lower side relative to the wheel axis, and the splash guard comprises a third elimination route in which a radially outside of the offset wall and the cutout portion communicate to each other via the radially inside of the offset wall.
 8. The braking device according to claim 5, wherein the splash guard comprises a fixing plate fixed to the knuckle, a wall with holes standing from the fixing plate towards the rotor, and a plurality of cooling holes constituted with through-holes passing through the wall with holes.
 9. The braking device for vehicle according to claim 3, wherein the wall with holes discontinues at lower side of the wheel axis CW, and a portion of the offset wall 15, where the offset wall 15 discontinues at lower side of the wheel axis CW, and a portion of the wall with holes 14, where the wall with holes 14 discontinues, are connected together.
 10. The braking device according to claim 6, wherein the splash guard comprises a fixing plate fixed to the knuckle, a wall with holes standing from the fixing plate towards the rotor, and a plurality of cooling holes constituted with through-holes passing through the wall with holes.
 11. The braking device according to claim 7, wherein the splash guard comprises a fixing plate fixed to the knuckle, a wall with holes standing from the fixing plate towards the rotor, and a plurality of cooling holes constituted with through-holes passing through the wall with holes. 